These wholly informal gatherings usually attract several hundred amateur telescope makers and users, men, women and children, and a drive to Stellafane makes an interesting week-end. Come in your old clothes, or if you haven't that much this sad year, come anyway. If you camp, bring along your camp outfit–there's plenty of room–and if you don't, there's a hotel in the village.

AS WAS stated explicitly in "Amateur Telescope Making," (the instruction book from which the many telescopes described from month to month in this department of the magazine were made) most workers make the concave mirror of their reflecting telescopes by hand, and this method has no drawbacks except to the lazy. But if one wishes to do it with a machine and actually enjoys concocting a machine–in other words, if the worker is possessed of the true mechanical instinct– then a machine is the thing to have and one need make no apology for it. One of the more serious addicts of the telescope making hobby, Mr. Byron L. Graves of Los Angeles (336 South June Street) has made such a machine, essentially the Porter type shown at B, Figure 3, page 151 of "Amateur Telescope Making."

Mr. Graves, who was formerly with the Ford Motor Company and later had much to do with airplane development in California, obtained suggestions and help directly from Mr. Porter in nearby Pasadena. Later at our request he described his fun in the following letters.

"With the new edition of 'Amateur Tele scope Making' in one hand and a saw in the other, I built a bench and mounted on it the Porter grinder and polisher, assembled out of old parts picked up around junk piles–with the exception of the gears, which are standard stock Boston, as well as the mounts for the bearings. You are mistaken; the grinder is not an engineer's job. I know little or nothing about engineering, having been engaged in the Ford assembling and selling business–operating Ford branches–for 19 years previous to 1926.

"I had the good fortune to meet the back yard astronomer's friend, Mr. Russell W. Porter, who is busy on the big 200-inch job over at 'Cal Tech,' but not too busy to talk to an amateur telescope maker. He told me the proper speed to use on the machine, namely 4 r.p.m. for the main table (revolving) on which rests the tool, and 1 or 2 r.p.m. for the mirror disk (in the opposite direction ) . The stroke speed is regulated for about 45 per minute. Any length stroke may be had by simply sliding the crank pin on the old Barnes face plate in or out. In grinding I speeded up to 55, with corresponding increase of speed in table and mirror. When it came to final polishing I used a weight to balance the load so that the mirror just about touched the tool

"I got pretty well discouraged once or twice when I overshot the mark and missed the parabola by about half an inch. I don't know when I have spent as many pleasant evenings as I have had grinding and polishing and figuring my little six inch mirror. The results? Well, I can count the braces on the big tower at the Mount Wilson Observatory from my back yard–over 20 miles away. My stars don't have tails on them, either, and they have a dark spot in the center under focus and the same over. I never had seen another reflecting telescope or speculum, so that Irish preacher Ellison did a pretty good job of instructing by book. By the way, if that fellow lived on this side of the Atlantic I would join hie' church and attend every Sunday morning, For, if he can preach as well as he describes this telescope thing, I wouldn't care wha1i religion he put out. He told just one lie in the whole book, namely, the time he takes to make a six-inch speculum from start to finish."

Some months after receiving the above letter, Mr. Graves was asked how he was making out. This is what he replied:

"I've been so busy on this new hobby) that I have neglected my home and family to say nothing of business affairs. Porter came over from Pasadena and gave my first attempt the 'once over'. He said she looked O.K. but of course the mirror didn't amount to much–I think he said she had spherical adenoids due to too tight lacing. I loosened her up and she now shows a round image of a star in or out of focus.

"The enclosed photograph will give you some idea of how the thing looks. My neighbor on the north said it wouldn't do to have a fire in this neighborhood, as the firemen would certainly try to couple an engine suction hose to the thing. Neighbor on the south made a remark which came to me through the 'grape vine telegraph namely their maid to our maid to my wife said it looked like 'Spark Plug.' Well, I did: cover the end up with an old felt hat one night and threw a blanket over the rest of it.

"Standard six inch cast iron pipe fitting were used for the mount and it is as solid as the rock of ages. The only part on the, job that I didn't make in my 'nut' shop back of the garage was the rack and pinion for focusing. I bought this for a dollar from a second-hand moving picture supply house. The pipe fittings cost eight dollars and a half.

"The setting circles were made of brass bands and fastened on with small pins like those used for fastening the nameplates on electric motors. I had to remove the threads on the short nipple and in the flange at its base in order to tilt the polar axis to 34O, our latitude. I drilled a couple of holes through flange and nipple and inserted bolts–one on either side–on which to hinge the nipple while making the adjustment. Then I locked it in place by means of a bolt acting as a set-screw (thread in the flange) as you will see by the photograph.

"The tube is made of heavy gage black iron electric welded. I squirted it with three coats of DUCO primer and four coats of regular finishing DUCO, rubbing down with fine emery paper and water after each coat. Two more coats of primer would have filled it perfectly but it doesn't look bad for an outdoor finish."

BETWEEN the fire-plug mounting that when suitably dressed up looked like the old hoss "Spark Plug" of the well-known comics, and the neighbors' pertinent or impertinent comments, Mr. Graves appears to have had his money's worth of fun. Just look at the pedestal he used six-inch pipe fittings. Then contrast it with some of the one-inch fittings that some have used. That eight fifty was a good investment in rigidity and in appearance too. To emphasize the value of rigid mountings in even a light breeze, here is a note written by Dr. T. A. Jaggar, the volcanologist. He is referring to Mount Harkness, California, 8000 feet high. "The entire mountain top," he says, "is shaken by strong winds and the seismographs (mounted in a closed excavation in its top) show a very irregular record on windy days. Puffs and gusts of wind produce records of tremor with considerable amplitude. Because a telescope amplifies vibrations it is fully as sensitive to shakes as a seismograph. Even Mr. Graves' six-inch pipe fittings can be no stiffer than Mount Harkness. It is hard to overdo in the matter of providing for rigidity in a mounting.

Mr. Graves spoke of the time it takes to make a six-inch speculum. Ellison has set up a record of something like six hours from the beginning of the grinding to the end of figuring, but few of us are Ellisons. It is a fact that most new workers will spend about 30 evenings making a speculum. Well, what of it if it's all fun, as Mr. Graves says?

Don't forget the two gatherings of amateur telescope enthusiasts–at Springfield' Vermont, July 25 and Pittsburgh, August 8-9.

The Society for Amateur Scientists (SAS) is a nonprofit research and educational organization dedicated to helping people enrich their lives by following their passion to take part in scientific adventures of all kinds.